Objective： To analyze the current situation of syphilis in the sexually transmitted diseases （STDs） clinic, from January 1994 to December 2002 was studied. Methods： All syphilis patients were confirmed by history,...Objective： To analyze the current situation of syphilis in the sexually transmitted diseases （STDs） clinic, from January 1994 to December 2002 was studied. Methods： All syphilis patients were confirmed by history, physical examination, dark-field microscopy of samples taken from the chancre or satellite lymph nodes,or positive serological tests. Results： From 1994 to 2002, there were 2067 cases of early syphilis, accounting for 20.01% （2067/10330） of all STD cases. The annual proportion of syphilis cases among all STD cases from 1994 to 2002 was 0.57%, 0.53%, 3.54%, 16.20%, 31.29%, 27.88%, 25.63%, 17.11%, 10.48%, respectively. Of 2067 syphilis patients,49.64% （1026/2067） were male and 50.36% （1041/2067） were female. 44.75% （925/2067） of all cases presented with primary syphilis, 44.90% （928/2067） with secondary syphilis, 9.77% （202/2067） with latent syphilis （without any conspicuous clinical signs or symptoms）, and 0.58% （12/2067） with congenital syphilis. The 30-39 year old cohort accounted for the largest proportion, at 37.68% （779/2067） of all syphilis cases. The 20-29 year old cohort also accounted for a large proportion, at 37.20% （769/2067） of all cases,followed by the 40-49 year old cohort, at 17.95% （371/2067）. Syphilis was most prevalent among the unemployed,self-employed laborers, and office workers in decreasing order. The majority of cases were graduates of either primary school, high school, or college. Of all syphilis cases, 87.86% （1816/2067） were married, and 12.14%（251/2067, including children） were unmarried. 76.78% （1587/2067） of all cases were acquired through extramarital intercourse. 14.03% （290/2067） of cases were infected by their spouses. 0.58% （12/2067） of cases were due to vertical transmission. 8.61% （178） of cases were acquired through indirect contact. Conclusion： The proportion of syphilis infection among all STDs remained stable from 1994 to 1995,quickly and dramatically increased from 1996 to 1999,and then gradually tapered down from 2000 to 2002. The incidence of congenital syphilis infections increased throughout the study period.展开更多
The properties of circulating gas have a significant effect on sintering with flue gas recirculation,and the influence of CO in sintering process was investigated.The results show that the post-combustion of CO conduc...The properties of circulating gas have a significant effect on sintering with flue gas recirculation,and the influence of CO in sintering process was investigated.The results show that the post-combustion of CO conducts in sinter zone when flue gas passes through the sintering bed,which releases much heat and reduces the consumption of solid fuel.The ratio of coke breeze can be reduced from 5% to 4.7% with 2% CO in circulating flue gas.In addition,with the increase of CO content in circulating flue gas,the combustion efficiency of fuel is improved,and the flame front is increased slightly while still matches with the heat transfer front.These are beneficial to increasing the maximum temperature and prolonging the high temperature duration,especially in the upper layer of sintering bed.As a consequence,the productivity,vertical sintering velocity and quality of sinter are improved.展开更多
Collective pitch control and individual pitch control algorithms were present for straight-bladed vertical axis wind turbine to improve the self-starting capacity.Comparative analysis of straight-bladed vertical axis ...Collective pitch control and individual pitch control algorithms were present for straight-bladed vertical axis wind turbine to improve the self-starting capacity.Comparative analysis of straight-bladed vertical axis wind turbine(SB-VAWT) with or without pitch control was conducted from the aspects of aerodynamic force,flow structure and power coefficient.The computational fluid dynamics(CFD) prediction results show a significant increase in power coefficient for SB-VAWT with pitch control.According to the aerodynamic forces and total torque coefficient obtained at various tip speed ratios(TSRs),the results indicate that the blade pitch method can increase the power output and decrease the deformation of blade;especially,the total torque coefficient of blade pitch control at TSR 1.5 is about 2.5 times larger than that of fixed pitch case.Furthermore,experiment was carried out to verify the feasibility of pitch control methods.The results show that the present collective pitch control and individual pitch control methods can improve the self-starting capacity of SB-VAWT,and the former is much better and its proper operating TSRs ranges from 0.4 to 0.6.展开更多
The article presents the results of experimental studies of the physical mechanisms and magnetic switching dynamics of films with one or two magnetic nanolayers under an irradiation picosecond and femtosecond laser pu...The article presents the results of experimental studies of the physical mechanisms and magnetic switching dynamics of films with one or two magnetic nanolayers under an irradiation picosecond and femtosecond laser pulses and also the samples of data recording devices on the spin storage medium are described. The study used a film with perpendicular anisotropy （Tb22Co5Fe73/Pr6O11/Tb29Co5Fe76, Tb25Co5Fe70/Al2O3, Tb22Co5Fe73, Tb19Co5Fe76） and films planar single-axis magnetic anisotropy （Co80Fe20/Pr6O11/CO30Fe70）. The magnetic switching of magnetic layers under action the magnetic field of a spin current is the most important for practical use in elements of spintronic. The spin current can also be realized using short electrical pulses. On the basis of this mechanism, the high-speed recording of information on the spin carrier has been realized.展开更多
OBJECTIVE: To better understand the working mechanism of acupuncture, we investigated the skin electrical impedance distribution around acupoints, and the impedance changes at 12 original acupoints bilaterally after b...OBJECTIVE: To better understand the working mechanism of acupuncture, we investigated the skin electrical impedance distribution around acupoints, and the impedance changes at 12 original acupoints bilaterally after bending the limbs.METHODS: We measured the skin electrical impedance in three study subjects in the frequency range of 40 to 10 k Hz using the four-electrode method with a sharp probe and a large reference electrode.A measurement matrix of 7 mm × 7 mm with spacing of 2.0(or 3.0) mm was measured to obtain 2 D impedance mapping of acupoints. The impedance spectra of 12 original acupoints were measured at the 0° position and the 90° position.RESULTS: The electrical impedance of some acupoints, such as Yangchi(TE 4), was 16 times lower than that of the surrounding area, showing a recognizable small central area of low impedance with a diameter of less than 4 mm. In contrast, other acupoints, such as Laogong(PC 8), had an electrical impedance that was not significantly different from that of the surrounding area. When the limb was bent from a straight position(0o) to a vertical position(90o), the electrical impedance of the 12 original acupoints showed varied trends, either increasing or decreasing by a factor of up to ten times, or remaining at the same level.CONCLUSION: Not all acupoints tested show the property of low impedance, which might be related to the varied depth of the openings of superficial collaterals. The unexpected dependence of acupoint impedance on limb angle is a novel discovery, which implies that the channel paths are located in interstitial structures in the limbs. It might be possible to determine an optimized limb position for each particular acupuncture treatment in clinical practice.展开更多
Snow-cover parameters are important indicator factors for hydrological models and climate change studies and have typical vertical stratification characteristics. Remote sensing can be used for large-scale monitoring ...Snow-cover parameters are important indicator factors for hydrological models and climate change studies and have typical vertical stratification characteristics. Remote sensing can be used for large-scale monitoring of snow parameters. In SAR(Interferometric Synthetic Aperture Radar) technology has advantages in detecting the vertical structure of snow cover. As a basis of snow vertical structure detection using In SAR, a scattering model can reveal the physical process of interaction between electromagnetic waves and snow. In recent years, the In SAR scattering model for single-layer snow has been fully studied;however, it cannot be applied to the case of multi-layer snow. To solve this problem, a multi-layer snow scattering mode is proposed in this paper, which applies the QCA(Quad-Crystal Approximation) theory to describe the coherent scattering characteristics of snow and introduces a stratification factor to describe the influence of snow stratification on the crosscorrelation of SAR echoes. Based on the proposed model, we simulate an In SAR volumetric correlation of different types of multi-layer snow at the X band(9.6 GHz). The results show that this model is suitable for multi-layer snow, and the sequence of sub-layers of snow has a significant influence on the volumetric correlation. Compared to the single layer model, the multi-layer model can predict a polarization difference in the volumetric correlation more accurately and thus has a wider scope of application. To make the model more available for snow parameter inversion, a simplified multi-layer model was also developed.The model did not have polarization information compared to that of the full model but showed good consistency with the full model. The phase of the co-polarization In SAR volumetric correlation difference is more sensitive to snow parameters than that of the phase difference of the co-polarization In SAR volumetric correlation and more conducive to the development of a parameter-inversion algorithm. The model can be applied to deepen our understanding of In SAR scattering mechanisms and to develop a snow parameter inversion algorithm.展开更多
文摘Objective： To analyze the current situation of syphilis in the sexually transmitted diseases （STDs） clinic, from January 1994 to December 2002 was studied. Methods： All syphilis patients were confirmed by history, physical examination, dark-field microscopy of samples taken from the chancre or satellite lymph nodes,or positive serological tests. Results： From 1994 to 2002, there were 2067 cases of early syphilis, accounting for 20.01% （2067/10330） of all STD cases. The annual proportion of syphilis cases among all STD cases from 1994 to 2002 was 0.57%, 0.53%, 3.54%, 16.20%, 31.29%, 27.88%, 25.63%, 17.11%, 10.48%, respectively. Of 2067 syphilis patients,49.64% （1026/2067） were male and 50.36% （1041/2067） were female. 44.75% （925/2067） of all cases presented with primary syphilis, 44.90% （928/2067） with secondary syphilis, 9.77% （202/2067） with latent syphilis （without any conspicuous clinical signs or symptoms）, and 0.58% （12/2067） with congenital syphilis. The 30-39 year old cohort accounted for the largest proportion, at 37.68% （779/2067） of all syphilis cases. The 20-29 year old cohort also accounted for a large proportion, at 37.20% （769/2067） of all cases,followed by the 40-49 year old cohort, at 17.95% （371/2067）. Syphilis was most prevalent among the unemployed,self-employed laborers, and office workers in decreasing order. The majority of cases were graduates of either primary school, high school, or college. Of all syphilis cases, 87.86% （1816/2067） were married, and 12.14%（251/2067, including children） were unmarried. 76.78% （1587/2067） of all cases were acquired through extramarital intercourse. 14.03% （290/2067） of cases were infected by their spouses. 0.58% （12/2067） of cases were due to vertical transmission. 8.61% （178） of cases were acquired through indirect contact. Conclusion： The proportion of syphilis infection among all STDs remained stable from 1994 to 1995,quickly and dramatically increased from 1996 to 1999,and then gradually tapered down from 2000 to 2002. The incidence of congenital syphilis infections increased throughout the study period.
基金Projects(51174253,51304245)supported by the National Natural Science Foundation of ChinaProject(2013bjjxj015)supported by the Outstanding and Creative Doctor Scholarship of Central South University,ChinaProject supported by the Hunan Provincial Innovation Foundation for Postgraduate,China
文摘The properties of circulating gas have a significant effect on sintering with flue gas recirculation,and the influence of CO in sintering process was investigated.The results show that the post-combustion of CO conducts in sinter zone when flue gas passes through the sintering bed,which releases much heat and reduces the consumption of solid fuel.The ratio of coke breeze can be reduced from 5% to 4.7% with 2% CO in circulating flue gas.In addition,with the increase of CO content in circulating flue gas,the combustion efficiency of fuel is improved,and the flame front is increased slightly while still matches with the heat transfer front.These are beneficial to increasing the maximum temperature and prolonging the high temperature duration,especially in the upper layer of sintering bed.As a consequence,the productivity,vertical sintering velocity and quality of sinter are improved.
基金Project (E201216) supported by Heilongjiang Provincial Natural Science Foundation,China
文摘Collective pitch control and individual pitch control algorithms were present for straight-bladed vertical axis wind turbine to improve the self-starting capacity.Comparative analysis of straight-bladed vertical axis wind turbine(SB-VAWT) with or without pitch control was conducted from the aspects of aerodynamic force,flow structure and power coefficient.The computational fluid dynamics(CFD) prediction results show a significant increase in power coefficient for SB-VAWT with pitch control.According to the aerodynamic forces and total torque coefficient obtained at various tip speed ratios(TSRs),the results indicate that the blade pitch method can increase the power output and decrease the deformation of blade;especially,the total torque coefficient of blade pitch control at TSR 1.5 is about 2.5 times larger than that of fixed pitch case.Furthermore,experiment was carried out to verify the feasibility of pitch control methods.The results show that the present collective pitch control and individual pitch control methods can improve the self-starting capacity of SB-VAWT,and the former is much better and its proper operating TSRs ranges from 0.4 to 0.6.
文摘The article presents the results of experimental studies of the physical mechanisms and magnetic switching dynamics of films with one or two magnetic nanolayers under an irradiation picosecond and femtosecond laser pulses and also the samples of data recording devices on the spin storage medium are described. The study used a film with perpendicular anisotropy （Tb22Co5Fe73/Pr6O11/Tb29Co5Fe76, Tb25Co5Fe70/Al2O3, Tb22Co5Fe73, Tb19Co5Fe76） and films planar single-axis magnetic anisotropy （Co80Fe20/Pr6O11/CO30Fe70）. The magnetic switching of magnetic layers under action the magnetic field of a spin current is the most important for practical use in elements of spintronic. The spin current can also be realized using short electrical pulses. On the basis of this mechanism, the high-speed recording of information on the spin carrier has been realized.
基金Supported by the National Natural Science Foundation of China(No.11374016,No.91221202)Medicineschool of electronics engineering and computer science Joint Seed Fund 2016,Peking University
文摘OBJECTIVE: To better understand the working mechanism of acupuncture, we investigated the skin electrical impedance distribution around acupoints, and the impedance changes at 12 original acupoints bilaterally after bending the limbs.METHODS: We measured the skin electrical impedance in three study subjects in the frequency range of 40 to 10 k Hz using the four-electrode method with a sharp probe and a large reference electrode.A measurement matrix of 7 mm × 7 mm with spacing of 2.0(or 3.0) mm was measured to obtain 2 D impedance mapping of acupoints. The impedance spectra of 12 original acupoints were measured at the 0° position and the 90° position.RESULTS: The electrical impedance of some acupoints, such as Yangchi(TE 4), was 16 times lower than that of the surrounding area, showing a recognizable small central area of low impedance with a diameter of less than 4 mm. In contrast, other acupoints, such as Laogong(PC 8), had an electrical impedance that was not significantly different from that of the surrounding area. When the limb was bent from a straight position(0o) to a vertical position(90o), the electrical impedance of the 12 original acupoints showed varied trends, either increasing or decreasing by a factor of up to ten times, or remaining at the same level.CONCLUSION: Not all acupoints tested show the property of low impedance, which might be related to the varied depth of the openings of superficial collaterals. The unexpected dependence of acupoint impedance on limb angle is a novel discovery, which implies that the channel paths are located in interstitial structures in the limbs. It might be possible to determine an optimized limb position for each particular acupuncture treatment in clinical practice.
基金supported by the National Natural Science Foundation of China (Grant Nos. 41471065 & 41471066)the International Partnership Program of Chinese Academy of Sciences (Grant No. 131C11KYSB20160061)+1 种基金the Science & Technology Basic Resources Investigation Program of China (Grant No. 2017FY100502)the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDA19070201)
文摘Snow-cover parameters are important indicator factors for hydrological models and climate change studies and have typical vertical stratification characteristics. Remote sensing can be used for large-scale monitoring of snow parameters. In SAR(Interferometric Synthetic Aperture Radar) technology has advantages in detecting the vertical structure of snow cover. As a basis of snow vertical structure detection using In SAR, a scattering model can reveal the physical process of interaction between electromagnetic waves and snow. In recent years, the In SAR scattering model for single-layer snow has been fully studied;however, it cannot be applied to the case of multi-layer snow. To solve this problem, a multi-layer snow scattering mode is proposed in this paper, which applies the QCA(Quad-Crystal Approximation) theory to describe the coherent scattering characteristics of snow and introduces a stratification factor to describe the influence of snow stratification on the crosscorrelation of SAR echoes. Based on the proposed model, we simulate an In SAR volumetric correlation of different types of multi-layer snow at the X band(9.6 GHz). The results show that this model is suitable for multi-layer snow, and the sequence of sub-layers of snow has a significant influence on the volumetric correlation. Compared to the single layer model, the multi-layer model can predict a polarization difference in the volumetric correlation more accurately and thus has a wider scope of application. To make the model more available for snow parameter inversion, a simplified multi-layer model was also developed.The model did not have polarization information compared to that of the full model but showed good consistency with the full model. The phase of the co-polarization In SAR volumetric correlation difference is more sensitive to snow parameters than that of the phase difference of the co-polarization In SAR volumetric correlation and more conducive to the development of a parameter-inversion algorithm. The model can be applied to deepen our understanding of In SAR scattering mechanisms and to develop a snow parameter inversion algorithm.
